For about twenty years, development has been underway on metering devices combined with seals for bottles or plastic containers for dispensing liquid or free-flowing substances into the bottles or containers onto which these metering devices are applied. Even though, as already noted above, such metering devices were already developed roughly twenty years ago, the latter have only been on the market for a little while. The initial idea was to offer medication together with a relatively small bottle, so that a traveler could take his or her medication together with a beverage without having to give any special thought to corresponding beverages or first having to go into a restaurant to obtain a corresponding, suitable beverage. This initial idea has today been largely abandoned. Such metering devices made out of plastic are today being offered for a great many, varied, liquid, free-flowing or even solid active substances present in tablet form. They make it possible to precisely maintain a specific mixing ratio of active substance to bottle contents. For example, plant fertilizers continue to be offered in relatively large bottles or containers, which then are to be added in small liquid doses. For example, only an amount of 10 milliliters of a plant protection product or insecticide, pesticide or fungicide has to be added to a watering can with five liters of water. A threaded lid is most often used as a measuring cup when such an amount is to be dispensed from a two-liter plastic bottle. Experience shows that these measuring cups are hardly used, and a user meters by eye, and hence practically always meters too much. This is ecologically and economically disadvantageous.
Metering closures suitable for dispensing active substances in solid form most often have a somewhat more complex structural design, since these active substances are most often present in blister packs, so that the latter are protected against light and moisture until the time they are to be dispensed into a liquid. In particular in the case of beverages, these active substances are vitamins, which are not stable in the liquid phase, and also decompose when exposed to light. WO2008/002160 shows a typical example of such metering closures. In such metering closures, the blister pack is most often configured and dimensioned in such a way that its welded edge is non-positively and positively held with the threaded part of the seal between a bottleneck and lateral wall of the closure part. The tablet in the blister pack can be ejected by means of a piercing mechanism, which is held above the blister pack and can be actuated by a guided pressure head. A protective cap is most often held over the piercing mechanism and pressure head, and must be removed prior to initial actuation.
If the content to be dispensed in such a metering device is liquid or free-flowing, use is usually made of a device having a cap that incorporates a sealed chamber, and this chamber is opened by a relative movement between this chamber and a piercing mechanism, so that the content of the chamber gets into the container. For example, in a solution known from CN201235991Y, the piercing mechanism is fixedly secured to the lower part of this metering closure, and given an abductive movement of the sealing cap in which the sealed chamber is secured, the membrane that seals the chamber is cut open. A very similar metering closure with a receiving chamber in the cap of the closure is known from JP2006176193.
GB2471994A shows a metering device comprised of a lower closure part and an applied cap, wherein a chamber is here molded into the lower part of the metering closure, and incorporates a piercing mechanism that can be displaced into a lower position after removing a cap, and thereby punches open the metering chamber, which is closed at its lower end by a membrane.
All known metering devices with a metering container integrated therein are conceived in such a way that the metering container has a diameter exhibiting maximally the inner diameter of the bottleneck. If the metering container is secured to the upper part of the metering device, this diameter is again reduced by the wall thickness of the metering container.
For example, if a quantity of 50 milliliters is to be dispensed into a bottle having a bottleneck with an inner diameter of 22 millimeters, the metering chamber, or the metering container, would have to have a height of 13 centimeters. Bearing in mind that a piercing mechanism must also be present, which is to perform a certain stroke and exhibits a pressure head, it can be assumed that the height of such a metering device would practically have to measure 15 centimeters. However, this is unpractical and unusable in every aspect. Bearing in mind that a liter bottle has a height of over 35 centimeters, for example, and a metering device with a height of roughly 15 centimeters is to be applied hereon, there would have to be more than half a meter distance between two shelves in a sales rack. This would be completely uneconomical, and such a bottle would also be impractical to transport and also store in the household.